JP7497238B2 - Portable Polishing Machine - Google Patents

Description

The present invention relates to a portable grinder.

Portable polishing machines have been known in the past that include an electric motor, an output shaft arranged parallel to the motor shaft of the electric motor and to which the rotation of the motor shaft is transmitted, and a polishing section that is connected to the output shaft and performs a polishing motion due to the rotation of the output shaft. For example, the following Patent Documents 1 and 2 disclose a sander that includes two such shafts. In this type of sander, the rotation of the motor shaft can be decelerated and transmitted to the output shaft and, in turn, to the polishing section. Furthermore, in a sander such as that disclosed in Patent Document 2, that is, a sander in which a battery is used as the power source for the electric motor and the battery is arranged to protrude rearward from the housing, the electric motor is arranged on the opposite side of the battery with respect to the output shaft, so that the center of gravity of the sander can be prevented from being excessively biased toward the battery. As a result, the distribution of the pressing force when the sander is pressed against the workpiece is made uniform, enabling uniform polishing.

International Publication No. 2018/168421 JP 2013-129016 A

However, the above-mentioned sanders leave room for improvement in terms of the layout within the device. For example, in a sander with two shafts arranged in parallel, the size in the direction in which the two shafts are aligned is inevitably large, making the sander less easy to handle. This problem is not limited to sanders with two shafts arranged in parallel, but is common to various portable grinders that have two or more shafts arranged in parallel.

According to one aspect of the present invention, a portable grinding machine is provided. The portable grinding machine includes an electric motor having a motor shaft, an output shaft arranged parallel to the motor shaft and configured to transmit the rotation of the motor shaft, a grinding unit connected to the output shaft and configured to perform grinding motion by the rotation of the output shaft, a first bearing that rotatably supports the output shaft, and a second bearing that rotatably supports the output shaft and is arranged closer to the grinding unit than the first bearing in the axial direction in which the output shaft extends. The first bearing and the second bearing are arranged in positions that do not overlap with the components located at the outermost radial positions of the components of the electric motor when viewed in the shaft arrangement direction in which the motor shaft and the output shaft are arranged in parallel.

According to this portable grinding machine, the components of the electric motor do not interfere with the first bearing and the second bearing that support the output shaft. Therefore, the distance between the motor shaft and the output shaft can be reduced compared to when at least one of the first bearing and the second bearing overlaps with the component located radially outermost among the components of the electric motor (hereinafter also referred to as the outermost component) as viewed in the shaft arrangement direction. Therefore, the size of the portable grinding machine in the shaft arrangement direction can be reduced. For example, when the first bearing overlaps with the outermost component of the electric motor as viewed in the shaft arrangement direction, the output shaft, the first bearing, the retainer that holds the first bearing, and the outermost component are aligned in the shaft arrangement direction. On the other hand, according to this aspect, the distance between the motor shaft and the output shaft can be reduced by a maximum of the arrangement space of the first bearing and the retainer within the range where the motor shaft and the outermost component do not come into contact.

According to one aspect of the present invention, the first bearing may be arranged so as to partially overlap the electric motor when viewed in the axial direction. This aspect allows the distance between the motor shaft and the output shaft to be further reduced.

According to one aspect of the present invention, the portable grinder may include a controller configured to control operation of the electric motor.

According to one aspect of the present invention, the controller may be disposed on the opposite side of the output shaft to the motor shaft in the shaft arrangement direction. According to this aspect, the distance between the controller and the electric motor is relatively large, so that the controller is less susceptible to the effects of heat generated by the electric motor.

According to one aspect of the present invention, the controller may be disposed in a position that at least partially overlaps with the output shaft in the axial direction. According to this aspect, the size of the portable grinder in the axial direction can be reduced compared to a case in which the controller is disposed in a position farther from the grinding unit than the output shaft in the axial direction.

According to one aspect of the present invention, the portable grinding machine may include a battery mounting section. The battery mounting section may be disposed on the opposite side of the output shaft to the motor shaft in the shaft arrangement direction, and may be capable of detachably mounting a battery as a power source for the electric motor. The battery mounting section may be disposed to hold the battery in a state inclined so as to move away from the output shaft from the second bearing side toward the first bearing side. The controller may be disposed between the output shaft and the battery mounting section in the shaft arrangement direction, inclined so as to move away from the output shaft from the second bearing side toward the first bearing side. According to this aspect, since the battery and the controller are disposed at an angle, the size of the portable grinding machine in the axial direction can be reduced compared to when the battery and the controller are disposed parallel to the axial direction.

According to one aspect of the present invention, the portable polisher may be equipped with a battery.

According to one aspect of the present invention, in the above-mentioned aspect in which the battery mounting section is arranged at an angle, the portable grinding machine may include a housing that accommodates the electric motor, the output shaft, the first bearing, the second bearing, and the controller. The housing may have a shape and size that allows the user to grip the side opposite the second bearing relative to the first bearing in the axial direction. The battery mounting section may be located at an end of the housing opposite the motor shaft relative to the output shaft in the shaft arrangement direction. According to this aspect, since the battery mounting section is arranged at an angle, the battery attached to the battery mounting section is prevented from protruding outward in the axial direction from the grippable part of the housing. Therefore, when the user grips the housing to perform grinding work, it is possible to prevent the battery from interfering with the user's arm. Moreover, the part of the housing that the user can grip can be secured large along the shaft arrangement direction. This makes it easier for the user to grip the housing. Furthermore, when the battery is arranged at an angle as described above, the center of gravity of the portable grinding machine is likely to be biased toward the battery side relative to the output shaft, but if the grippable part is spread toward the battery side, the user can grip a part close to the center of gravity. This allows the user to hold the portable grinder more stably with less force.

According to one aspect of the present invention, the housing may have a size and shape that does not protrude beyond the polishing portion in the direction from the output shaft toward the motor shaft. This aspect can prevent the housing from interfering with the polishing operation. For example, if the housing protrudes beyond the polishing portion, the housing may come into contact with a convex portion of the workpiece or a surrounding object during the polishing operation, causing a problem that the polishing portion cannot reach every corner of the area that needs to be polished. According to this aspect, such a problem does not occur. According to the portable polishing machine of the above-mentioned aspects, the distance between the motor shaft and the output shaft can be reduced, so that this aspect can be easily realized even when manufacturing a small portable polishing machine (i.e., a portable polishing machine with a small polishing portion when viewed in the axial direction).

According to one aspect of the present invention, the portable grinder may include a housing that contains at least an electric motor, an output shaft, a first bearing, and a second bearing. The housing may have a size and shape that does not protrude beyond the grinding section in the direction from the output shaft toward the motor shaft. This aspect also prevents the above-mentioned problems from occurring.

According to one aspect of the present invention, each of the first bearing and the second bearing may be a ball bearing. According to this aspect, the first bearing and the second bearing can support a large load.

FIG. 2 is a left side view of the sander according to one embodiment of the present invention. FIG. FIG. FIG. 2 is a partial cross-sectional view showing a portion of the sander in cross-section. 4 is a partial cross-sectional view taken along line AA of FIG. 3, showing a portion of the sander in cross-section. 3 is a cross-sectional view of the sander taken along line BB in FIG. 2. FIG. 4 is a right side view showing the inside of the sander with the right housing removed.

The following describes an embodiment of the present invention with reference to the drawings. In the following embodiment, an orbital sander (hereinafter, simply referred to as a sander) 10 is exemplified as a portable sander. The sander 10 exemplified in this embodiment is a small type of sander, i.e., a type with a relatively small sanding area, and is also called a mini sander.

As shown in Figures 1 and 2, the sander 10 includes a grinding unit 30, an electric motor 50, and an output shaft 61. The motor shaft 52 of the electric motor 50 and the output shaft 61 are arranged parallel to each other. One end of the output shaft 61 is connected to the grinding unit 30. As will be described in detail later, the sander 10 is configured such that the rotational driving force of the electric motor 50 is transmitted to the output shaft 61, and the grinding unit 30 performs a grinding motion due to the rotation of the output shaft 61.

In the following description, the direction in which the motor shaft 52 and the output shaft 61 are aligned in parallel is defined as the front-rear direction of the sander 10. In the front-rear direction, the side where the motor shaft 52 is located is defined as the front side, and the side where the output shaft 61 is located is defined as the rear side. The direction in which the motor shaft 52 and the output shaft 61 extend is defined as the up-down direction of the sander 10. In the up-down direction, the side where the grinding section 30 is located is defined as the lower side, and the opposite side is defined as the upper side. In addition, the direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction of the sander 10. In the left-right direction, the right side when viewed from the rear to the front side is defined as the right side of the sander 10, and the opposite side is defined as the left side of the sander 10.

As shown in Figures 1 to 3, the sander 10 includes a housing 20. The housing 20 has a cylindrical shape with a closed top end. The sander 10 is a so-called palm type, and the upper part 22 of the housing 20 has a shape and size that allows the user to hold it. In other words, the upper part 22 also functions as a handle for the user to hold with one hand when using the sander 10. As shown in Figure 3, the upper part 22 is formed so that its left-right width gradually decreases downwards to make it easier for the user to grip. The housing 20 is formed by connecting a right housing 20a and a left housing 20b (see Figure 3) as halves to each other with a plurality of bolts 21 (see Figure 2).

As shown in FIG. 4, the electric motor 50 is accommodated in the housing 20. The electric motor 50 is disposed in the approximate center of the housing 20 in the vertical direction, near the front end of the housing 20 in the front-rear direction (see FIG. 4), and in the approximate center of the housing 20 in the left-right direction (see FIG. 6). The electric motor 50 is called a can motor and has a motor case 51 made of thin sheet metal. The motor case 51 accommodates the rotor, stator, and other components of the electric motor 50 (not shown). In this embodiment, the electric motor 50 is a brushed motor. By adopting a can motor as the electric motor 50, it is no longer necessary to assemble the related parts one by one into the housing, improving the ease of assembly. However, the electric motor 50 may be a brushless motor. A motor shaft 52 extends from the lower end of the motor case 51. A pulley 67 is fixed around the extended motor shaft 52.

As shown in FIG. 4, the output shaft 61 is rotatably supported by the first bearing 62 and the second bearing 63 in the housing 20. In this embodiment, each of the first bearing 62 and the second bearing 63 is a ball bearing. As described above, the output shaft 61 extends in the vertical direction parallel to the motor shaft 52. The output shaft 61 is arranged so as to be located at the center of the grinding section 30 described later when viewed in the vertical direction. The first bearing 62 supports the vicinity of the upper end of the output shaft 61. The first bearing 62 is fixed to the housing 20 via a bearing retainer 64. The second bearing 63 is located lower than the first bearing 62 in the vertical direction (in other words, closer to the grinding section 30 than the first bearing 62) and supports the vicinity of the center of the output shaft 61. The second bearing 63 is fixed to the housing 20 via a bearing retainer 65. The bearing retainer 65 also supports the motor case 51.

As shown in FIG. 4, the first bearing 62 and the second bearing 63 are arranged in a position that does not overlap with the radially outermost component (also called the outermost component) among the components of the electric motor 50 when viewed in the front-rear direction (in other words, the direction in which the motor shaft 52 and the output shaft 61 are arranged in parallel). In other words, the first bearing 62 is located above the upper end of the outermost component in the vertical direction, and the second bearing 63 is located below the lower end of the outermost component in the vertical direction. The "radial direction" here refers to a direction perpendicular to the axial direction in which the motor shaft 52 extends. In this embodiment, as is clear from FIG. 4, the outermost component is the motor case 51. When the electric motor 50 does not have a motor case 51, the outermost component is generally a stator if the electric motor 50 is an inner rotor type motor, and a rotor if the electric motor 50 is an outer rotor type motor.

Furthermore, in this embodiment, as shown in FIG. 4, the first bearing 62 and the second bearing 63 are arranged so as to partially overlap the electric motor 50 when viewed in the up-down direction. In the example shown in FIG. 4, the motor case 51, which is the outermost component of the electric motor 50, overlaps with the outer rings and bearing balls of the first bearing 62 and the second bearing 63. However, only the outer rings may overlap. Also, if the electric motor 50 does not have a motor case 51, the first bearing 62 and the second bearing 63 may partially overlap with the outermost component determined according to the structure of the electric motor 50.

As shown in FIG. 4, a pulley 66 is fixed around the output shaft 61. The pulley 66 is adjacent to the second bearing 63 below the second bearing 63. The pulley 66 is disposed at a position overlapping the pulley 67 when viewed in the front-rear direction. An endless belt 68 is wound between the pulleys 66 and 67 (see FIGS. 4, 5, and 7). In this embodiment, the diameter of the pulley 66 is larger than the diameter of the pulley 67. Therefore, the rotation of the motor shaft 52 is decelerated and transmitted to the output shaft 61. However, the rotation of the motor shaft 52 may be transmitted to the output shaft 61 without being decelerated.

As shown in FIG. 4, a fan 91 is further attached around the output shaft 61, below the pulley 66. The space housing the fan 91 is connected to a dust collection nozzle 92. The dust collection nozzle 92 extends rearward from the lower and rear ends of the housing 20. A cloth dust bag, a synthetic resin dust box, or a hose connected to a dust collector (none of which are shown) can be attached to the dust collection nozzle 92.

The polishing section 30 is located at the bottom of the sander 10 and includes a polishing pad 31, a base 32, and clampers 33a and 33b. The polishing pad 31 and base 32 have a generally rectangular shape when viewed in the vertical direction. The base 32 is disposed on top of the polishing pad 31, and the two are connected by a bolt (not shown) that extends in the vertical direction.

Sanding paper (not shown) is attached to the polishing pad 31 using clampers 33a and 33b. Specifically, the clamper 33a extends above the base 32 along the right edge and rear edge of the base 32, and a lever 34a is attached to its front end. The clamper 33b extends above the base 32 along the left edge and front edge of the base 32, and a lever 34b is attached to its rear end. With the sanding paper placed on the bottom surface of the polishing pad 31, the lever 34a is operated to sandwich the rear end of the sanding paper between the part of the clamper 33a along the rear edge and the base 32, and the lever 34b is further operated to sandwich the front end of the sanding paper between the part of the clamper 33b along the front edge and the base 32, thereby fixing the sanding paper to the polishing pad 31. The bottom surface of the polishing pad 31 functions as a polishing surface when the sander 10 is in use.

As shown in Figures 1 and 2, the polishing section 30 protrudes forward in the front-rear direction beyond the housing 20. In other words, the housing 20 has a size and shape that does not protrude forward beyond the polishing section 30. Therefore, during polishing work using the sander 10, the housing 20 does not come into contact with the convex parts of the workpiece or surrounding objects, preventing the polishing section 30 from reaching every corner of the area that needs polishing.

As shown in FIG. 4, the grinding section 30 is connected to the output shaft 61 via a bearing 69. Specifically, the bearing 69 is sandwiched between the fan 91 and the base 32 so as to surround the lower end of the output shaft 61. The bearing 69 is arranged in an eccentric state with respect to the output shaft 61. The inner ring of the bearing 69 is supported by a balancer 71 arranged below it. The balancer 71 is fixed to the output shaft 61 by a bolt 72 that screws into a screw hole formed in the lower end of the output shaft 61. The balancer 71 has a shape in which the center of gravity is biased in the opposite direction to the eccentric direction of the bearing 69 with respect to the output shaft 61. This makes it possible to suppress the occurrence of vibration caused by the eccentricity of the bearing 69 with respect to the output shaft 61.

5 and 6, the grinding section 30 is further connected to the housing 20 via four feet 73. The feet 73 are disposed near the four corners of the rectangular base 32. The feet 73 have a generally cylindrical shape extending in the vertical direction. The upper and lower ends of the foot 73 are formed as narrowed sections having a relatively small diameter. An O-ring 74 is disposed around the upper narrowed section, which engages with the housing 20 via the O-ring 74. An O-ring 75 is disposed around the lower narrowed section, which engages with the inner surface of the boss 35 of the base 32 via the O-ring 75. The foot 73 can be tilted in the vertical direction while crushing the O-rings 74 and 75. A sleeve 76 is provided around the foot 73 to prevent dust from entering. The sleeve 76 is made of sponge and has elasticity, and is attached in a slightly crushed state. This maintains the high dust resistance of the foot.

As shown in Figures 1, 2 and 4, a battery mounting section 45 is provided on the rear side of the output shaft 61 in the front-rear direction (in other words, the side opposite the motor shaft 52). More specifically, the battery mounting section 45 is located at the rear end of the housing 20. The battery mounting section 45 is configured to receive the battery 40, which serves as a power source for the electric motor 50, in a sliding manner from above to below. In this embodiment, the battery 40 has a rated voltage of 18V. However, the battery 40 may have a rated voltage greater than 18V.

The battery mounting section 45 is arranged at an incline so that it is farther away from the output shaft 61 the further upward (in other words, from the second bearing 63 side to the first bearing 62 side). In other words, the battery mounting section 45 is equipped with a guide rail that is received in a guide groove formed in the battery 40 and a terminal block that holds a terminal for electrically connecting to the battery 40, and these guide rails and terminal blocks are arranged at an incline so that they are farther away from the output shaft 61 the further upward. As a result, when the battery 40 is mounted on the battery mounting section 45, it is held in an inclined state so that it is farther away from the output shaft 61 the further upward.

When the battery 40 is attached to the battery attachment section 45, the battery 40 is held as far down as possible in the vertical direction without interfering with the dust collection nozzle 92. At this time, the upper end of the battery 40 is at approximately the same position as the upper end of the housing 20 in the vertical direction. In other words, by holding the battery 40 at an incline as described above, the upper end of the battery 40 is prevented from protruding significantly upward beyond the housing 20. Therefore, when the user grasps the housing 20 from the rear, the battery 40 does not interfere with the user's arm. Moreover, since the battery attachment section 45 is arranged at an incline as described above, the upper part 22 of the housing 20 for the user to grasp can be secured large toward the rear. Therefore, the user can easily grasp the housing 20. Moreover, when the battery 40 is arranged at an incline as described above, the center of gravity of the sander 10 is easily biased toward the battery 40 side rather than the output shaft 61 located at the center of the grinding section 30, but if the upper part 22 is widened toward the rear, the user can grasp a part closer to the center of gravity. Therefore, the user can stably grasp the sander 10 with less force.

As shown in Figures 4 and 5, a controller 80 is housed within the housing 20. The controller 80 is electrically connected to the terminals of the battery mounting section 45 and the electric motor 50, and controls the operation of the electric motor 50 by controlling the power supplied from the battery 40 to the electric motor 50. In this embodiment, the controller 80 includes a high temperature protection circuit, an overcurrent protection circuit, and an overdischarge protection circuit. However, one or two of these protection circuits may be omitted.

As shown in Figures 4 and 5, the controller 80 is disposed on the opposite side of the output shaft 61 from the electric motor 50 in the front-rear direction. In other words, the controller 80 is disposed between the output shaft 61 and the battery mounting section 45 in the front-rear direction. With this arrangement, the distance between the controller 80 and the electric motor 50 is relatively large. As a result, the controller 80 is less susceptible to the effects of heat generated by the electric motor 50.

Furthermore, as shown in Figs. 4 and 5, the controller 80 is disposed at a position where it partially overlaps with the output shaft 61 in the vertical direction. That is, the vertical position of the controller 80 is a position where the controller 80 and the output shaft 61 partially overlap when viewed in a direction perpendicular to the vertical direction. In this embodiment, the controller 80 partially overlaps with the output shaft 61 when viewed in the front-rear direction. However, the controller 80 may partially overlap with the output shaft 61 when viewed in another direction perpendicular to the vertical direction (i.e., a direction other than the front-rear direction). The controller 80 may also entirely overlap with the output shaft 61. With this arrangement, the size of the sander 10 in the vertical direction can be reduced compared to when the controller 80 is disposed above the output shaft 61.

Furthermore, as shown in Figs. 4 and 5, the controller 80 is inclined so that it is farther away from the output shaft 61 the further upward it goes (in other words, the further it goes from the second bearing 63 side to the first bearing 62 side). In this way, by inclining the controller 80 in the same direction as the battery 40, the size of the sander 10 in the vertical direction can be reduced. In this embodiment, the inclination angle of the controller 80 is the same as the inclination angle of the battery mounting section 45. In addition, one of the widest faces of the controller 80 faces upward and forward, and the opposite widest face faces downward and rearward. By arranging in this way, the size of the sander 10 in the vertical direction can be further reduced.

As shown in FIG. 3, a switch 23 is provided on the upper front surface of the housing 20. The switch 23 is electrically connected to the controller 80. The switch 23 is provided to perform an operation for starting and stopping the electric motor 50. The switch 23 has two buttons. One button is a button for stopping the driving of the electric motor 50. The other button is a button for driving the electric motor 50, and each time the other button is pressed, the rotation speed of the electric motor 50 is changed sequentially by a predetermined number of steps.

The sander 10 described above operates as follows. First, when the user operates the switch 23 to drive the electric motor 50, the motor shaft 52 starts to rotate. The rotation of the motor shaft 52 is transmitted to the output shaft 61 via the pulleys 66, 67 and the belt 68. Since the bearing 69 connecting the output shaft 61 and the polishing unit 30 is eccentric with respect to the output shaft 61, as the output shaft 61 rotates (rotates), the polishing unit 30 performs an eccentric circular motion (orbital motion) around the output shaft 61 while squashing the O-rings 74, 75 arranged around the foot 73 and tilting the foot 73. In other words, the polishing unit 30 does not rotate by itself, but moves in a circular motion along the horizontal plane while maintaining its posture. In this state, when the bottom surface of the polishing unit 30 is pressed against the object to be polished, the eccentric circular motion of the polishing unit 30 acts as a polishing motion, and polishing is performed by the sanding paper attached to the bottom surface of the polishing unit 30.

According to the sander 10, the first bearing 62 and the second bearing 63 are arranged in a position that does not overlap with the outermost component (i.e., the component located at the outermost radial position) of the components of the electric motor 50 when viewed in the front-rear direction. Therefore, there is no interference between the components of the electric motor 50 and the first bearing 62 and the second bearing 63 that support the output shaft 61. Therefore, compared to the conventional sander, the motor shaft 52 and the output shaft 61 can be brought closer to each other in the front-rear direction. Therefore, the device size of the sander 10 in the front-rear direction can be reduced. In particular, in the above-mentioned embodiment, the first bearing 62 and the second bearing 63 are arranged so as to partially overlap with the electric motor 50 when viewed in the up-down direction. Therefore, the device size of the sander 10 in the front-rear direction can be further reduced. If the outer rings and bearing balls of the first bearing 62 and the second bearing 63 are overlapped with the electric motor 50 as in the above-mentioned embodiment, the distance between the motor shaft 52 and the output shaft 61 can be minimized.

By reducing the distance between the motor shaft 52 and the output shaft 61 in this way, it is possible to easily realize the above-mentioned configuration, in which the housing 20 has a size and shape that does not protrude forward beyond the polishing section 30, even in a small sander 10.

Although the embodiments of the present invention have been described above, the above-mentioned embodiments are intended to facilitate understanding of the present invention and do not limit the present invention. The present invention may be modified or improved without departing from its spirit, and the present invention includes equivalents. Furthermore, any combination or omission of each element described in the claims and specification is possible within the scope of solving at least part of the above-mentioned problems or achieving at least part of the effects.

For example, if the diameter of the first bearing 62 is larger than the diameter of the second bearing 63, an arrangement may be adopted in which only the first bearing 62 partially overlaps with the outermost component when viewed in the vertical direction, and the second bearing 63 does not partially overlap with the outermost component when viewed in the vertical direction. Even in this case, the distance between the motor shaft 52 and the output shaft 61 may be minimized. In addition, the first bearing 62 and the second bearing 63 can be positioned at any position as long as they are positioned so as not to overlap with the outermost component of the electric motor 50 when viewed in the front-rear direction. Even in this way, the device size in the front-rear direction can be reduced compared to conventional sanders.

In addition, the sander 10 may be provided with a power cord for connecting to an AC power source instead of the battery 40 and the battery mounting section 45.

Furthermore, one or more additional shafts may be interposed between the motor shaft 52 and the output shaft 61. That is, the rotation of the motor shaft 52 may be transmitted to the output shaft 61 via one or more additional shafts.

Furthermore, the above-described embodiment is not limited to small orbital sanders, but can be applied to any portable polishing machine in which the motor shaft and the output shaft are arranged in parallel. For example, the above-described embodiment can also be applied to large orbital sanders (also called finishing sanders), random orbit sanders, polishers, etc.

10...sander 20...housing 20a...right housing 20b...left housing 21...bolt 22...upper part 23...switch 30...polishing part 31...polishing pad 32...base 33a, 33b...clamper 34a, 34b...lever 35...boss 40...battery 45...battery mounting part 50...electric motor 51...motor case 52...motor shaft 61...output shaft 62...first bearing 63...second bearing 64, 65...bearing retainer 66, 67...pulley 68...belt 69...bearing 71...balancer 72...bolt 73...foot 74, 75...O-ring 76...sleeve 80...controller 91...fan 92...dust collection nozzle

Claims (10)

A portable polishing machine, comprising:
an electric motor having a motor shaft;
an output shaft arranged in parallel with the motor shaft and configured to transmit rotation of the motor shaft;
a grinding section coupled to the output shaft and configured to undergo a grinding motion upon rotation of the output shaft;
a first bearing that rotatably supports the output shaft;
a second bearing that is disposed at a position closer to the grinding portion than the first bearing in an axial direction that is a direction in which the output shaft extends, and that rotatably supports the output shaft;
Equipped with
the first bearing and the second bearing are disposed at positions not overlapping with components positioned radially outwardly among components of the electric motor when viewed in a shaft arrangement direction in which the motor shaft and the output shaft are arranged in parallel ,
the component located most radially outward is a motor case when the electric motor includes a motor case, a stator when the electric motor does not include a motor case and is an inner rotor type, and a rotor when the electric motor does not include a motor case and is an outer rotor type;
The component located at the outermost radial direction is located between the first bearing and the second bearing as viewed in the shaft arrangement direction,
The first bearing and the second bearing are disposed at positions that partially overlap the component located at the outermost radial side when viewed in the axial direction.
Portable grinder. 2. The portable grinder of claim 1 ,
A portable sander comprising a controller configured to control operation of the electric motor. 3. The portable grinder of claim 2 ,
the controller is disposed on an opposite side of the output shaft from the motor shaft in the shaft arrangement direction. 4. The portable grinder according to claim 2 or 3 ,
The controller is disposed at a position at least partially overlapping with the output shaft in the axial direction. A portable grinding machine according to claim 3 or claim 4 which includes claim 3 as a dependent element,
a battery mounting portion that is disposed on an opposite side of the motor shaft with respect to the output shaft in the shaft arrangement direction and into which a battery serving as a power source for the electric motor can be detachably attached;
the battery mounting portion is disposed to hold the battery in a state inclined away from the output shaft as it moves from a second bearing side toward a first bearing side,
The controller:
When the battery is attached to the battery attachment portion, the battery attachment portion is disposed so as to entirely overlap the battery as viewed in the shaft arrangement direction,
When viewed in a direction perpendicular to the axial direction and the shaft arrangement direction, the shaft has a substantially rectangular shape having a longitudinal direction and a lateral direction,
A portable grinder disposed between the output shaft and the battery mounting portion in the shaft arrangement direction, with the longitudinal direction inclined so as to move away from the output shaft as it moves from the second bearing side to the first bearing side. 6. The portable grinder of claim 5 ,
A portable polishing machine comprising the battery. 7. The portable grinder according to claim 5 or 6 ,
a housing that accommodates the electric motor, the output shaft, the first bearing, the second bearing, and the controller;
the housing has a region that can be held by a user at a top portion on a side opposite to the second bearing with respect to the first bearing in the axial direction,
the battery attachment portion is adjacent to the grippable area in the shaft arrangement direction and is located at an end of the housing on an opposite side to the motor shaft with respect to the output shaft in the shaft arrangement direction,
When the battery is attached to the battery attachment portion, the battery protrudes beyond the grippable area in a direction from the second bearing toward the first bearing.
Portable grinder. 8. The portable grinder of claim 7 ,
The housing has a size and shape such that it does not protrude beyond the grinding portion in a direction from the output shaft toward the motor shaft. A portable grinder according to any one of claims 1 to 6 ,
a housing that accommodates at least the electric motor, the output shaft, the first bearing, and the second bearing;
The housing has a size and shape such that it does not protrude beyond the grinding portion in a direction from the output shaft toward the motor shaft. A portable grinder according to any one of claims 1 to 9 ,
The portable grinder, wherein each of the first bearing and the second bearing is a ball bearing.

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